UL 291:2016 pdf free download – STANDARD FOR SAFETY Automated Teller Systems.
5.6.12 The opening illustrated in Figure 5.8 may be used if, within the enclosure, there is no uninsulated live part or film-coated wire:
a) Less than “X” inches from the perimeter of the opening, as well as
b) Within the volume generated by projecting the perimeter “X” inches normal to its plane. MX” equals five times the diameter of the largest-diameter rod that can be inserted through the opening, but is not less than 4 inches (102 mm). In evaluating an opening, any barrier located within the volume is to be ignored unless it intersects the boundaries of the volume in a continuous closed line.
5.7 Interlocks and protective devices
5.7.1 An interlock provided for the purpose of protecting an operator or serviceman against injury or electric shock shall be of a type or in such a location that it requires an intentional operation to bypass.
5.7.2 The bypass means shall be such that the interlock is self-restoring as the unit is returned to its intended operation.
5.7.3 A protective device provided to remove a stored-energy charge from an internal circuit shall operate automatically when the circuit is de-energized.
5.8 Covers
5.8.1 An enclosure cover shall be hinged, sliding, pivoted or similarly attached so as to prevent its being removed if it:
a) Gives access to fuses or any other overcurrent protective device, the intended functioning of which requires renewal; or
b) Is necessary to open the cover in connection with the intended operation of the product.
5.8.2 If the fuse(s) enclosed is intended to provide protection to portions of internal circuits, such as may be used on a separate printed-wiring board or circuit subassembly to prevent excessive circuit damage resulting from a fault, a hinged cover is not required. The following or equivalent marking shall be indicated on the cover if the risk of electric shock is present:
“CAUTION — Circuit Fuse(s) — Disconnect Power Prior To Servicing.”
5.8.3 Where a hinged cover is required, it shall be provided with a latch, screw, or catch to hold it closed. The hinged cover of a product intended to be installed where it will be accessible to other than authorized personnel shall be provided with a key lock or with a screw requiring a tool for removal.
6 Corrosion Protection
6.1 Iron and steel parts, other than bearings and similar parts where such protection is impractical, shall be protected against corrosion by enameling, galvanizing, sherardizing, plating, or other means determined to be equivalent.
Exception No. 1: This requirement does not apply to minor parts, such as washers, screws, bolts, and similar parts if the failure of such unprotected parts would not be likely to result in a hazardous condition or adversely affect the operation of the product.
Exception No. 2: Parts made of stainless steel, polished or treated, if necessary, do not require additional protection against corrosion.
6.2 The requirement in 6.1 applies to all enclosures of sheet steel or cast iron and to all springs and other parts upon which proper mechanical operation may depend.
6.3 Bearing surfaces shall be of such materials and design as to resist binding due to corrosion.
6.4 Metal shall not be used in combinations such as to cause galvanic action.
7 Field-Wiring Connections
7.1 General
7.1.1 Wiring terminals or leads shall be provided for connection of conductors of at least the size required by the National Electrical Code, ANSI/NFPA 70.